Laminated protective sole



Jan. 5, 1960 L. P. FRIEDER ErAL LAMINATED PROTECTIVE SOLE Original Filed Feb. 10, 1955 2 Sheets-Sheet 1 in n N o 3 g m L 1 an 4 a Original Filed Feb. 10, 1955 Jan. 5, 1960 L. P. FRIEDER ETAL 2,920,008

LAMINATED PROTECTIVE SOLE 2 Sheets-Sheet 2 J- 5 E Q INVENTORS 197' TOANE Y United States atent LAMINATED PROTECTIVE soLE Leonard P. Frieder, Great Neck, and Walter S. Finken, Brooklyn, N.Y., assignors to Gentex Corporation, a corporation of Delaware Original application February 10, 1955, Serial No. 487,269, now Patent No. 2,808,663, dated October 8, 1957. Divided and this application March 22, 1957, Serial No. 648,464

2 Claims. (Cl. ism-'46 Our invention relates to a laminated protective sole and more particularly to a laminated protective sole which is compact, flexible, lightweight, and which has a high resistance to penetration by sharp objects.

This application is a division of our copending appli cation Serial No. 487,269, filed February 10, 1955, now Patent No. 2,808,663 issued October 8, 1957.

Safety shoes are known in the prior art for protecting thef oot of the wearer from injury by sharp objects which might penetrate the sole of an ordinary shoe. This protection may be afforded by a metal plate, or the like, inserted within the shoe as an inner sole or formed as a part of the sole during shoe manufacture. These metal plates are rigid and do not flex with the wearers foot. They do not permit shoes to bi-came" properly and are, therefore, uncomfortable and unhealthy. If a ligh'ter and more flexible material than metal is employed to permit the shoe to flex and breathe properly while providing the same measure of protection as metal, the shoe is extremely bulky and awkward. In the prior art, therefore, safety shoe designers are confronted with the problem of providing a safety shoe which has a high degree of resistance to penetration by sharp objects and yet is flexible, lightweight, and comfortable. 7

We have invented a laminated protective sole for shoes which affords a high degree of protection to the wearers foot. Our sole is compact, lightweight, flexible, and waterproof. It permits a shoe including the sole to flex with the foot of the wearer and to breathe properly. At the same time our sole has a high resistance to penetration' by sharp' objects and flying fragments. Our sole may be used in boots for combat troops as a protection against flying fragments from land mines, or the like. It may also be used in footwear of all types as a protection against sharp objects such as nails, glass, stone, and the like. It may be formed as a part of the safety shoe sole itself or it may be used as a separate inserted laminated protective sole in rubber boots, sneakers, moccasins, and the like.

One object of our invention is to provide a laminated protective sole which is compact and lightweight and which has a high resistance to penetration.

Another object of our invention is to provide a lam-' inated protective sole which has a high resistance to penetration and which flexes with the foot of the wearer.

Yet another object of our invention is to provide a laminated protective sole which may be inserted in any type of footwear or which may be formed as an integral part of a safety shoe sole.

Yet a further object of our invention is to provide a laminated protective sole which permits the shoe with which the sole is used to breathe properly.

A still further object of our invention is to provide a laminated protective sole which is water resistant.

Other and further objects of our invention will appear from the following description. 7

In general, our invention'contempla'tes the provision of a'laminated' protective'sole including a'stack of synthetic ture employed.

resin-impregnated, fibrous laminates. In one form of our invention adjacent laminates of the sole are separated by a thin film of material which is nonadherent with respect to the laminates. Adjacent laminates may be bonded to each other by spaced bonds extending through the nonadherent film. Loose stitching may be employed to prevent dissassembly of the stack when in use. In an alternateembodiment of our invention we cure the synthetic-resin-impregnated fibrous laminates of our sole individually and retain them in stacked relationship by a fused resin bond extending-through the stack over a minor area of the sole adjacent the heel or toe. If desired, a layer of leather, or canvas and sponge rubber, may be secured to the sole for comfort. Our laminated protective sole may be a partial sole or a whole sole and it may be formed as a separate laminated protective sole or be made an integral part of the sole of a safety shoe.

In the accompanying drawings which form part of the instant specification and which are to be read in conjunction therewith and in which like reference numerals are used to indicate like parts in the various views:

Figure l is a plan view of one form of our laminated protective sole.

Figure 2 is a perspective view, drawn on an enlarged scale, of the form of our laminated protective sole shown in Figure 1 with its leather layer removed;

Figure 3 is a fragmentary sectional view, drawn on an enlarged scale, taken along the line 3--3 of Figure 1, of our laminated protective sole.

Figure 4 is a plan view of the perforated, nonadherent film separating a pair of adjacent laminates of our laminated protective sole.

Figure 5 is a fragmentary sectional view, drawn on an enlarged scale, of a further form of our laminated protective sole;

Figure 6 is a plan view of another form of our laminated protective sole.

Figure 7 is a fragmentary sectional view of a safety shoe, the sole of which includes a form of our safety s'ole.

More particularly referring now to Figures 1 to 4 of the drawings, one form of our laminated protective sole, indicated generally by the reference character 10, includes a plurality of stacked fibrous, synthetic-resin-impregnated laminates 12, 1'4, 16, 18, 20, and 22'. Each of these laminates may be formed of any suitable matted, felted, woven, knitted, or braided fibrous material. Preferably, we employ a mat of spun glass fibers, but any other plastic material, such as nylon, or the like, may be used. The laminates are impregnated with a thermoplas tic or thermosetting resinous material, such, for example; as polyethylene plastic, allyl' plastic, polystyrene plastic, phenol formaldehyde,- or urea formaldehyde resins. Pref' erably, we employ a polyester resin, since this material may be cured at a sufiiciently low temperature such that the film, to be described hereinafter, disposed betweeri laminates will not fuse during curing.

Adjacent laminates are separated by a thin film of a. material which is nonadherent with respect to the fibrous, resin-impregnated laminates which it separates; For example, laminates 12 and 14 are separated by a film 24 and remaining pairs of adjacent laminates are separated by respective films 26, 28, 30', and 32. The films 24, 26, 28, 30 and 32 may be'formed of any material which remains flexible and does not fuse at the curing tempera-'- Such materials as cellophane, nylon Teflon, saran, or cellulose acetate may be used. Teflon ethylene polymer. A thin metal film may also be used to separate adjaceiit laminates'to prevent font-nation of a continuous bond between adjacent laminates during the curing process. Preferably, we employ cellophane.

Successive laminates of the stack of laminates making up ourprotective sole deflect differentially in resisting penetration by a sharp object. When a sharp object impinges on the lowest laminate 22 of the stack, successive laminates from the laminate 22 up through laminate 12 deflect differentially to distribute the penetrating force over successively larger areas. In other words, when under the action of such a penetrating force, the laminates from laminate 22 up through laminate 12 have successively larger radii of curvature. The end result of this differential deflection action of the laminates results in a distribution of the penetrating force over so large an area of laminate 12 that no injury to the foot of the wearer results. The entire force of penetration is dissipated before the sharp object passes through all the laminates. It will readily be understood that the nonadherent films 24, 26, 28, 30 and 32 prevent formation of a continuous bond between adjacent laminates during the curing of the stack of laminates. These films, therefore, permit the differential deflection action which contributes to the penetration-resisting property of our sole.

In order to enhance the penetration-resisting property of our sole and in order to retain the stacked laminates in assembled position, we provide a plurality of spaced bonds between adjacent laminates. Each of the nonadherent films 24, 26, 28, 30 and 32 is provided with a plurality of spaced perforations 34 over its surface. The relative disposition of these perforations 34 over the surface of one form of film, such as the film 24, is shown in Figure 4. We provide bonds 36 of resinous material extending through the perforations 34 in the films between adjacent laminates. These bonds 36 may conveniently be formed of the same material with which the laminates are impregnated during the molding process to be described hereinafter. When a sharp object impinges on the surface of the laminate 22, the bonds 36 between a pair of adjacent laminates must be sheared before the laminates. of the pair can deflect differentially with respect to one another to any appreciable degree. It will be seen, therefore, that the bonds 36 between adjacent laminates also resist the force of penetration, since they must be sheared before the laminates can deflect differentially.

It is to be noted that the spaced bonds 36 between one pair of adjacent laminates are staggered with respect to the bonds 36 between a succeeding pair of adjacent laminates. For example, the bonds 36 between laminates 12 and 14 are out of alignment with the bonds 36 between the adjacent laminates 14 and 16. This arrangement may advantageously be followed throughout the sole construction. It renders our sole moisture resistant by providing a labyrinth packing to resist the penetration of moisture from laminate 22 through the remainder of the laminates toward the foot of the wearer. It will be appreciated that each of the fibrous laminates 12, 14, 16, 18, 20, 22 is in some degree permeable, permitting the passage of water vapor therethrough. Vapor penetrating the laminate 22 may travel through a bond 36 between laminates 20 and 22. Because of our staggered arrangement of bonds, such moisture must then travel transversely through the laminate 20 before it arrives at a bond 36 between laminates 18 and 20 which permits its passage into laminate 18. It must travel a like circuitous passage through the remainder of the laminates before it reaches the interior of the shoe. Thus our construction provides a laminated protective sole which is moisture resistant.

When our laminated protective sole is to be formed separately and employed as an insert into an article of footwear, we may, for purposes of comfort add a layer of leather, or the like, 38 to the stacked assembly of laminates. A layer of a suitable glue 40 secures the layer of leather 38 to the top laminate 12 of the assembly. This is the form of our invention shown in Figure 3. In an other form of our laminated protective sole which may be used, for example, in rubber boots and the like, we may cement a layer of sponge rubber 42 to the upper laminate by glue 44. The rubber layer 42 may be covered with a thin canvas layer 46 secured to the upper surface of the layer 42 by glue 43.

It will be appreciated that by reason of the constant flexing of the laminated protective sole when in use many of the bonds 36 between adjacent laminates may become broken and the laminates may tend to become separated from each other. In order to ensure that the laminates are retained in the assembled state we fasten the assembly together by stitching 50. This stitching 50 includes legs 52 which pass through all the laminates and retain the laminates in assembled position with respect to each other. Stitching 50 is sufficiently loose to retain the flexible characteristic of the sole, While retaining the laminates in assembled position. In Figures 1 and 3 we have shown this stitching as extending along the axis of the inner sole 10 for purposes of convenience only. It is to be understood that stitching 50 may be of any configuration which retains the sole in the assembled state while retaining the flexible property of the sole. For example, in Figure 6 we have shown the laminated protective sole 10 as being provided with stitching 54 which follows the outline of the sole.

Referring now to Figure 7, we have shown our safety sole 10 in use as a filler sole formed as an integral part of a shoe sole. The protective sole 10 is disposed between the shoe outsole 56 and the insole 58. As is known in the art, a lip 60 formed on the underside of insole 58 is secured to the shoe welt 62 by stitching 64. The upper 66 is retained by stitching 64 between lip 60 and the welt 62. Stitching 68 secures the welt to the outsole 56. It will thus be seen that the Welt 62 retains our protective sole 10 in the space between insole 58 and outsole 56. In this position our protective filler sole replaces the cork filler customarily employed in shoe manufacture.

When our protective sole is made as a part of the shoe sole, as shown in Figure 7, the layer of leather 38 or the layer of rubber 42 and canvas 46 need not be employed. Moreover, since there is very little possibility that the laminates of which our sole is made will fall away from each other, stitching 50 may be omitted in this form of our invention, if desired. It may, however, be desirable to employ such stitching in this form of the invention to prevent the possible formation of uncomfortable bulges or corrugations in the laminates when they flex in ordinary use of the shoe. Since no serious difficulties arise in this form of our invention when the laminates separate, it is not essential that the bonds 36 between adjacent laminates be employed. If desired, they may be eliminated entirely and differential deflection of adjacent laminates to resist penetration would still be possible.

Our laminated protective soles may be formed by any convenient process. In one method a plurality of laminates of fibrous mat material separated by perforated sheets of nonadherent material are stacked on top of each other. The assembled stack is placed in a mold and the impregnating material forced into the sheets of fibrous mattered material and through the perforations 34 in the nonadherent films. This assembly is cured under heat and pressure to form a board from which soles are made. Parallel lengths of stitching 50 are then sewn from one end ofthe board to the other. The separation between the lines of stitching is determined by the width of the soles to be made from the board. If the soles are intended for use as separate inserts, a layer of a suitable material such as leather, canvas and sponge rubber, or the like, is gluedto the top. The assembly is then slit into strips corresponding to stampings, one right and the other left, of the same width shoe. The left and right foot stampings form pairs of laminated protective soles for insertion into the articles of footwear with which they are to be used. If the laminated protective soles are to be formed as part of a safety shoe sole, the stampings may be made immediately after molding of the board, and no separate leather or sponge rubber and canvas layers are employed. If desired, stitching 54 around the periphery of a stamped sole may be applied in place of the stitching 50 applied to the molded board before stamping. It is to be understood that, if desired, our protective sole may be a partial sole or a complete sole.

When our laminated protective sole is used as a separate insert, the form of our invention shown in Figure 3 or Figure 5 may be used. This form of our invention includes a layer 38 of leather, or a layer of rubber 42 and canvas 46, for comfort. Stitching 50 along the axis or the sole or stitching 54 around the periphery of the sole may be employed. If the wearer steps on a sharp object, such as a piece of broken glass, a nail, or the like, the protective sole resists penetration by the object. The force of penetration is resisted by the differential deflection between adjacent laminates after the bonds 36 break. Stitching 50 or 54 is loose to permit this differential deflection by retaining the laminates in assembled position. If bonds 36 have sufiicient strength to retain the laminates in assembled position in ordinary use, stitching 50 or 54 may be dispensed with. We prefer, however, to employ the stitching to prevent the laminates from falling away from each other in the event that the bonds 36 break. It will be understood also that, if desired, bonds 36 may be eliminated and stitching 50 used to retain the laminates in assembled position and permit differential deflection therebetween. In this case continuous, impervious films are disposed between adjacent laminates. Again we prefer to employ the staggered bonds 36 to enhance the penetration-resisting quality of the inner sole. The staggered arrangement of the bonds 36 renders our sole moisture resistant, since it provides a circuitous path for the passage of moisture through the sole. Our sole resists penetration by flying fragments resulting from explosions.

In the form of our invention shown in Figure 7, the protective filler sole is enclosed in the space between the shoe insole 58 and the shoe outsole 56 by the Welt 62. This form of our protective sole resists penetration in the same manner as the form of our invention shown in Figures 1 to 6. When the protective sole is formed as part of a safety shoe sole, we may dispense with stitching 50 or 54, since there is no possibility of the laminates falling away from each other as long as the welt 62 holds the insole and outsole together. Such stitching is advantageous in preventing uncomfortable corrugations being formed in the shoe sole. Similarly, in this form of our invention we may or may not, as desired, employ bonds 36.

Since the sewing 50 or 54 is loose, a slight separation of adjacent laminates between bonds 36 is permitted as the wearer lifts his foot. Air may enter into these separations between the laminates. When the wearer again steps on the sole, this air is forced out and the shoe is thus permitted to breathe. sole is sufliciently flexible that of the wearers foot.

It will be seen that we have accomplished the objects of our invention. We have provided a laminated protective sole which has a high resistance to penetration by sharp objects. Our laminated protective sole is compact, lightweight, and flexible. It permits the article of footwear with which it is used to breathe properly. Our sole may be used as an insert with any type of footwear or it may be made an integral part of a safety shoe. Further, our protective sole is moisture resistant.

It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations. This is contemplated by and is within the scope of our claims. It is further obvious that various changes may be made in details within the scope of our claims without departing from the spirit of our invention. It is, there fore, to be understood that our invention is not to be limited to the specific details shown and described.

Having thus described our invention, what we claim 1s:

1. A laminated protective sole including in combination a plurality of stacked fibrous laminates, said laminates impregnated with synthetic resin, a plurality of thin flexible films of material nonadherent with respect to said resin respectively disposed between adjacent laminates, said films substantially coextensive with said laminates, and means for retaining said laminates in stacked relationship.

2. A laminated protective sole as in claim 1 in which said nonadherent material is cellophane.

Our laminated protective it can follow the motions References Cited in the file of this patent UNITED STATES PATENTS 58,623 Elliott Oct. 9, 1866 87,942 Johnson et al. Mar. 16, 1869 148,770 Stanton Mar. 17, 1874 884,985 Mann Apr. 14, 1908 1,676,170 Troiel July 3, 1928 1,704,187 Glidden et al. Mar. 5, 1929 2,304,936 Lewis Dec. 15, 1942 2,312,841 Lewis Mar. 2, 1943 2,355,168 Kubovcik Aug. 8, 1944 2,383,052 Everston Aug. 21, 1945 2,502,774 Alianiello Apr. 4, 1950 2,641,068 Thompson June 6, 1953 2,736,109 Scholl Feb. 28, 1956 2,748,048 Russell May 29, 1956 FOREIGN PATENTS 12,516 Denmark Sept. 13, 1909 176,404 Great Britain Mar. 7, 1922 305,694 Great Britain Feb. 8, 1929 537,688 Great Britain July 2, 1941 

1. A LAMINATED PROTECTICE SOLE INCLUDING IN COMBINATION A PLURALITY OF STACKED FIBROUS LAMINATES, SAID LAMINATES IMPREGNATED WITH SYNTHETIC RESIN, A PLURALITY OF THIN FLEXIBLE FLIMS OF MATERIAL NONADHERENT WITH RESPECT TO SAID RESIN RESPECTIVELY DISPOSED BETWEEN ADJACENT LAMINATES, SAID FILMS SUBSTANTIALLY COEXTENSIVE WITH SAID LAMINATES, AND MEANS FOR RETAINING SAID LAMINATES IN STACKED RELATIONSHIP. 